Baptist churches sponsor nearly 4,000 Scout units representing more than 100,000 youths, according to the Boy Scouts of America.

That number could drop precipitously.

The Southern Baptist Convention, the country’s largest Protestant denomination, will soon urge its 45,000 congregations and 16 million members to cut ties with the Scouts, according to church leaders.

The denomination will vote on nonbinding but influential resolutions during a convention June 11-12 in Houston.

“There’s a 100% chance that there will be a resolution about disaffiliation at the convention,” said Richard Land, the longtime head of the Southern Baptists’ Ethics & Religious Liberty Commission, “and a 100% chance that 99% of people will vote for it.”

“Southern Baptists are going to be leaving the Boy Scouts en masse,” Land continued.

Roger “Sing” Oldham, a spokesman for the Southern Baptist Convention, emphasized that local congregations make their own decision on the Scouts.

But he, too, said he expects Baptist delegates, which the church calls “messengers,” to voice their disagreement with the BSA’s decision to allow gay youths.

“With this policy change, the Boy Scouts’ values are contradictory to the basic values of our local churches,” Oldham said.

Several religious groups with strong Scouting ties support the new policy.

“We have heard from both those who support the amended policy and those who would have preferred it would not have changed,” said BSA spokesman Deron Smith.

Faith-based organizations charter more than 70% of Scout chapters, providing meeting space and leadership, according to the BSA.

“There have been some organizations that have decided not to renew their charters with Scouting,” said Smith, “but we can’t quantify the impact of the amended policy.”

The National Jewish Committee on Scouting, the United Church of Christ, the Episcopal Church, the Unitarian Universalist Association and the Church of Jesus Christ of Latter-day Saints, which sponsors more Scout units than any other faith, all endorsed the change.

The National Catholic Committee on Scouting, which is run with oversight from a bishop, said Thursday that allowing gay youths in the Scouts does not conflict with church teaching. Each bishop will decide whether or not to allow churches in his diocese to charter Scout units, the committee added.

“We ask that Catholic Scouters and chartered organization heads not rush to judgment,” said Edward Martin, chairman of the National Catholic Committee on Scouting.

But the Rev. Derek Lappe, pastor of the Our Lady Star of the Sea Catholic Church in Bremerton, Washington, has already made up his mind.

“I do not feel that it is possible for us to live out, and to teach, the authentic truth about human sexuality within the confines of the Boy Scout’s new policy,” said Lappe.

There may soon be an alternative to the Scouts for social conservatives like Lappe.

John Stemberger, founder of On My Honor, a group that opposed the Scouts’ change in policy, plans to convene conservatives in Louisville, Kentucky, in June to consider forming a new Scout-like group, which could be up and running by the end of 2013.

“Churches and Scoutmasters are looking for leadership and direction,” said Stemberg, an attorney in Orlando, Florida.

A number of conservative religious denominations already sponsor their own groups.

For instance, the Southern Baptists have the Royal Ambassadors, an explicitly Christian program founded in 1908 for boys in first through sixth grade. (A similar group called Challengers equips older boys in “mission education.”)

The name comes from the New Testament, in which the Apostle Paul tells Christians to be “ambassadors for Christ.”

The estimated 31,000 Royal Ambassadors pledge “ to become a well-informed, responsible follower of Christ; to have a Christlike concern for all people; to learn how to carry the message of Christ around the world; to work with others in sharing Christ; and to keep myself clean and healthy in mind and body.”

While not as outdoorsy as the Boy Scouts, Ambassadors do camp and play sports, said Land, who was a member of the group during the 1950s. But instead of merit badges for archery and bird study, young Ambassadors earn patches for memorizing Bible verses and mission work.

Southern Baptists said they are preparing for a surge of interest in the Royal Ambassadors at their upcoming convention in Houston.

“We really have an opportunity here to strengthen our RA programs,” the Rev. Ernest Easley, chairman of the Southern Baptist Convention’s Executive Committee, said in a sermon last Sunday, “and to get the boys in a program where they’re going to be protected, where there’s a high moral standard and where they will have an opportunity to learn about camping, missions, evangelism in the local church.”